Observation 97268: Agaricus L.

When: 2012-06-13

Collection location: Bad Godesberg, Germany [Click for map]

Who: deuteragenie

No specimen available

In group (+- 10), on grass along street.
Smell: mushroom.

Agaricus campestris ?



Proposed Names

84% (1)
Recognized by sight
28% (1)
Recognized by sight

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Eye3 = Observer’s choice
Eyes3 = Current consensus


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DNA sequences does not help
By: Gerhard Koller (Gerhard)
2012-06-15 14:32:27 CDT (-0500)

if there are not people who can identify the species in the field :)
There are so many misapplied data in the bases around the world. Nowhere we can attain 100 % I am afraid.

By: deuteragenie
2012-06-15 14:23:07 CDT (-0500)

That’s clear.

Just trying to apply my books, while considering which microscope to buy :) Thanks for your tips. It also helps me understand what to look after and that, well, probably many claimed recognized specimens are not 100% sure.

When will portable DNA analyzers be available ? :)

Could be nivescens/osecanus,
By: Gerhard Koller (Gerhard)
2012-06-15 14:11:42 CDT (-0500)

but without spore form and stuff we will never exactly know what it is … there are some other possibilities too. You would need a monography.

Review of arvenses
By: deuteragenie
2012-06-15 14:04:47 CDT (-0500)

macrosporus : probably not, no pink base in sight
excellens: id
augustus : clearly not
essetei: annulus was fragile, so probably not
silvicola: not yellow enough, habitat does not fit
… we are left with arvensis and nivescens
nivescens seems to fit better, as Bon describe it as hard to turn yellow and “globuleux”, which was the case for many non-collected specimens.

By: deuteragenie
2012-06-14 15:52:17 CDT (-0500)

Correction: cap turn yellow when mistreated, but on older specimen.

It is Arvenses group.
By: Gerhard Koller (Gerhard)
2012-06-14 14:59:45 CDT (-0500)

But I cannot tell species by photos and naked eye.
I would go for one of the last mentioned but not arvensis itself.

More info
By: deuteragenie
2012-06-14 14:22:00 CDT (-0500)

Smell pleasant, but not really anises. Difficult to find something that accurately depicts it. “Spring” maybe.

Base of the stipe turns yellow a bit. Rest of the stipe and flesh immutable.
Annulus is brittle and thin, indented on the inside. Can be removed upwards. Turns black when handled.
Maximum cap size: 13cm.
Flesh is consistent.
Cap does not turn yellow/ocre when mistreated.
Cap on old specimen has metallic reflection.

See additional pics.

In Arvenses
By: Gerhard Koller (Gerhard)
2012-06-13 16:28:17 CDT (-0500)

there are a bunch of species that are very similar which can only be distinguished by spores and macrochemical reactions like Shaffer’s reaction.
Also look for A. macrosporus, macrosporoides, excellens, urinascens and more.
Typical arvensis has a strong smell of aniseed. Others like urinascens smell more like Agaricus bisporus the “Zuchtchampignon”.

Arvenses probably
By: deuteragenie
2012-06-13 16:07:38 CDT (-0500)

Certainly the smell was pleasant so it should be in section arvenses. It did not remind of anise though. I will collect a more mature specimen which I believe may help identifying the specie. Note: they were at the same location last year.

Does not look like xanthoderma: cap is too convex for that according to the drawing in Bon.

Agaricus campestris
By: Gerhard Koller (Gerhard)
2012-06-13 12:38:31 CDT (-0500)

is smaller and turns brownish-reddish on cutting.
This turns yellow. It belongs either to the xanthoderma or the arvensis group I would say. Since the smell is not nauseous I tend to arvensis group. But there are so many in-between. Can you define the smell more accurate? How does the color change of the flesh look after a few minutes especially in the base of the stipe? Another thing to pay attention to is the annulus (ring): can you peel it off the stipe downwards or upwards?

Yellow colors
By: walt sturgeon (Mycowalt)
2012-06-13 12:36:26 CDT (-0500)

are wrong for Agaricus campestris.

Created: 2012-06-13 12:33:20 CDT (-0500)
Last modified: 2012-06-15 14:05:42 CDT (-0500)
Viewed: 123 times, last viewed: 2017-06-13 03:01:57 CDT (-0500)
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